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81.
P-cadherin, a transmembrane molecule similar to E-cadherin involved in the cell-cell adhesion, and catenins form complexes between its cytoplasmic domain and the cytoskeleton. Five cell lines, 108 specimens of oral squamous cell carcinomas (OSCC), 9 metastasis and 10 of normal oral mucosa were examined to evaluate P-cadherin expression and cellular localization by immunohistochemistry and western-blotting. In normal oral mucosa there was a membranous expression only in basal and parabasal layers. 91 cases (84%) showed membranous/cytoplasmic positivity, whereas 17 cases (16%) were negative. In particular, while well-differentiated carcinomas showed P-cadherin upregulation, the protein was homogeneously hypo- or unexpressed in low-differentiated carcinomas. There was a statistically significant correlation between P-cadherin expression and tumour grading: G3 tumours had a lower score than G1-G2 tumours (P<0.05). When analysed for prognostic significance, patients with no P-cadherin expression (score 0) had poorer overall and diseases-free survival rates than the P-cadherin-expressing group (score 1) (P=0.0463 and P=0.0471, respectively). Western blotting analysis of cell lines and tissue samples confirmed immunohistochemical findings. When cell staining pattern of positive cases was examined, 52 cases showed a prevalent membranous pattern, while 39 had a prevalent cytoplasmic pattern. Cases with prevalent cytoplasmic staining showed high rates of lymph node metastases (P>0.05), and regional relapse (P <0.05) and poorer survival rates than the group with prevalent membranous expression (P<0.0001). An absent P-cadherin expression could constitute a hallmark of aggressive biological behaviour in oral squamous cell carcinoma.  相似文献   
82.
Phosphoinositides, synthesized from myo-inositol, play a critical role in the development of growth cones and in synaptic activity. As neurons cannot synthesize inositol, they take it up from the extracellular milieu. Here, we demonstrate that, in brain and PC12 cells, the recently identified H(+)/myo-inositol symporter HMIT is present in intracellular vesicles that are distinct from synaptic and dense-core vesicles. We further show that HMIT can be triggered to appear on the cell surface following cell depolarization, activation of protein kinase C or increased intracellular calcium concentrations. HMIT cell surface expression takes place preferentially in regions of nerve growth and at varicosities and leads to increased myo-inositol uptake. The symporter is then endocytosed in a dynamin-dependent manner and becomes available for a subsequent cycle of stimulated exocytosis. HMIT is thus expressed in a vesicular compartment involved in activity-dependent regulation of myo-inositol uptake in neurons. This may be essential for sustained signaling and vesicular traffic activities in growth cones and at synapses.  相似文献   
83.
A 328-bp sequence from exon 1 of the gene for aquaporin-2 (AQP2) was compared in 12 mammalian species, representing as many eutherian orders. This sequence encodes the N-terminal half of this kidney- specific water channel protein. Most amino acid replacements, as well as an insertion, have occurred in extracellular loops connecting the transmembrane helices, in agreement with a lower functional importance of these loops. Phylogenetic analyses were performed with parsimony, distance, and maximum-likelihood methods. The AQP2 data set, alone as well as in combination with previously published alpha A-crystallin protein sequences, strongly supports a clade consisting of elephant, hyrax, aardvark, and elephant shrew, reaching bootstrap values of 99%. This finding fully agrees with the only other presently available sequence data sets that include these taxa, those of von Willebrand factor and interphotoreceptor retinoid-binding protein, and suggests that this extended paenungulate clade is one of the most conspicuous superordinal groupings in eutherian phylogeny. Some support was obtained for an artiodactyl/perissodactyl clade, while the grouping of pholidotes with edentates was contradicted.   相似文献   
84.
EB Brown  ES Wu  W Zipfel    WW Webb 《Biophysical journal》1999,77(5):2837-2849
Multiphoton fluorescence photobleaching recovery (MP-FPR) is a technique for measuring the three-dimensional (3D) mobility of fluorescent molecules with 3D spatial resolution of a few microns. A brief, intense flash of mode-locked laser light pulses excites fluorescent molecules via multiphoton excitation in an ellipsoidal focal volume and photobleaches a fraction. Because multiphoton excitation of fluorophores is intrinsically confined to the high-intensity focal volume of the illuminating beam, the bleached region is restricted to a known, three-dimensionally defined volume. Fluorescence in this focal volume is measured with multiphoton excitation, using the attenuated laser beam to measure fluorescence recovery as fresh unbleached dye diffuses in. The time course of the fluorescence recovery signal after photobleaching can be analyzed to determine the diffusion coefficient of the fluorescent species. The mathematical formulas used to fit MP-FPR recovery curves and the techniques needed to properly utilize them to acquire the diffusion coefficients of fluorescently labeled molecules within cells are presented here. MP-FPR is demonstrated on calcein in RBL-2H3 cells, using an anomalous subdiffusion model, as well as in aqueous solutions of wild-type green fluorescent protein, yielding a diffusion coefficient of 8.7 x 10(-7) cm(2)s(-1) in excellent agreement with the results of other techniques.  相似文献   
85.
Mature mouse sperm cells incubated in an isotonic buffer with cloned DNA capture DNA molecules over a 15 min period. Spermatozoa incubated with pSV2CAT plasmid in either circular or linear form were used to fertilize mouse eggs in vitro. Sequences complementary to pSV2CAT were identified in approximately 30% of 250 progeny by Southern blotting. A genomic library was constructed from the DNA of a positive mouse. Three positive clones were identified and two adjacent HincII restriction fragments of 240 and 370 bp showed identical sequences to the corresponding fragments of the pSV2CAT plasmid. F1 progeny showed paternal and maternal transmission of the transgenes from founders. CAT gene expression was detected on tissues of adult F1 individuals, preferentially on tails and muscle. We conclude that transgenic mice can be obtained using sperm cells as foreign DNA vectors.  相似文献   
86.
Epibatidine (exo-2-(2'-chloro-5'-pyridyl)-7-azabicyclo[2.2.1]heptane), a natural compound isolated from the skin of the Ecuadorian poison frog Epipedobates tricolor, is the most potent nicotinic acetylcholine receptor (nAChR) agonist reported to date. In order to visualize and quantify in vivo these receptors in human brain using Positron Emission Tomography (PET), [18F]norchlorofluoroepibatidine (exo-2-(2'-[18F]fluoro-5'-pyridyl)-7-azabicyclo[2.2.1]heptane), a fluorine-18 (t(1/2): 110 min) radiolabeled derivative of epibatidine has been designed. The corresponding 2'-bromo-, 2'-iodo- and 2'-nitro exo-2-(5'-pyridyl)-7-azabicyclo[2.2.1]heptane analogues as labeling precursors, as well as norchlorofluoroepibatidine as a reference compound have been synthesized by reductive, stereoselective, palladium-catalyzed Heck-type coupling between an N-Boc protected azanorbornene and the corresponding halopyridine. [18F]Norchlorofluoroepibatidine has been radiolabeled with fluorine-18 by nucleophilic aromatic substitution from the corresponding Boc-protected halo- and nitro precursors using [18F]FK-K222 complex in DMSO by conventional heating (at 150-180 degrees C for 10 min) or microwave activations (at 100 Watt, for 1 to 2.5 min), followed by TFA-removal of the protective group. Typically, using the microwave activation procedure, 60-80 mCi (2.22-2.96 GBq) of pure [18F]norchlorofluoroepibatidine could be obtained in less than 2 h (110-115 min) from the bromo labeling precursor, with specific radioactivities of 1.5-2.5 Ci/micromol (55.5-92.5 GBq/micromol) calculated for End of Bombardment. The preliminary PET experiments in baboon (Papio papio) with [18F]norchlorofluoroepibatidine show a high uptake and a rapid accumulation of the radiotracer into the brain within 30 min. In the thalamus, a nAChR rich area, uptake of radioactivity reached a maximum at 40 min (10% I.D./100 mL tissue). The ratio of radioactivity thalamus/cerebellum (the latter being a nAChR poor area) was 2 at 40 min and increased with time, up to 4.3 at 160 min. Its specific regiodistribution and its high ratio of specific-to-nonspecific binding confirm the ideal profile of [18F]norchlorofluoroepibatidine as a suitable radioligand for PET imaging of nAChRs in the brain.  相似文献   
87.
The occurrence of vimentin, a specific intermediate filament protein, has been studied by immunoflourescence microscopy in tissue of adult and embryonic brain as well as in cell cultures from nervous tissue. By double imminofluorescence labeling, the distribution of vimentin has been compared with that of subunit proteins of other types of intermediate filaments (glial fibrillary acidic [GFA] protein, neurofilament protein, prekeratin) and other cell-type specific markers (fibronectin, tetanus toxin receptor, 04 antigen). In adult brain tissue, vimentin is found not only in fibroblasts and cells of larger blood vessels but also in ependymal cells and astrocytes. In embryonic brain tissue, vimentin is detectable as early as embryonic day 11, the earliest stage tested, and is located in radial fibers spanning the neural tube, in ventricular cells, and in blood vessels. At all stages tested, oligodendrocytes and neurons do not express detectable amounts of vimentin. In primary cultures of early postnatal mouse cerebellum, a coincident location of vimentin and GFA protein is seen in astrocytes, and both types of filament proteins are included in the perinuclear aggregates formed upon exposure of the cells to colcemid. In cerebellar cell cultures of embryonic-day-13 mice, vimentin is seen in various cell types of epithelioid or fibroblastlike morphology but is absent from cells expressing tetanus toxin receptors. Among these embryonic, vimentin-positive cells, a certain cell type reacting neither with tetanus toxin nor with antibodies to fibronectin or GFA protein has been tentatively identified as precursor to more mature astrocytes. The results show that, in the neuroectoderm, vimentin is a specific marker for astrocytes and ependymal cells. It is expressed in the mouse in astrocytes and glial precursors well before the onset of GFA protein expression and might therefore serve as an early marker of glial differentiation. Our results show that vimentin and GFA protein coexist in one cell type not only in primary cultures in vitro but also in the intact tissue in situ.  相似文献   
88.
目的: 当前评估左心室容量和功能仍常用正常值范围,个体化分析也仅使用体表面积进行校正。尚缺少个体化因素相关的大样本参考值和预计公式。方法: 本研究纳入美国加州洛杉矶县南湾地区1200名健康志愿者,其中男807女393,年龄20岁-94岁,心脏CT造影(CTA),经过高精度三维成像技术处理,计算左心室容积在收缩和舒张过程中的连续动态变化,测定左心室(LV)容量和功能指标:舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)、射血分数(EF)和心输出量(CO)。将以上指标与一般特征指标进行多因素相关分析,以探索正常人预计值计算公式。结果: 男性除LVEF小于女性外(P<0.001),其余各指标均大于女性(P<0.001)。多元线性回归分析提示, 性别、年龄、身高和体质量均为EDV、ESV、SV的独立影响因子(P<0.001); 而CO仅受年龄、性别、体质量显著影响(P<0.001),但与身高无关(P>0.05)。CO的预测公式CO (L·min-1)= 6.963+0.446(Male) -0.037×年龄(yr)+0.013×体质量(kg)。结论: 性别、年龄、身高、体质量均影响左心室容量和功能,建立预测值计算公式,对心血管疾病的无创评估和个体化精准医疗具有重要参考价值。  相似文献   
89.
The online platform “Wikiplantbase #Toscana” provides a framework where the full set of georeferenced floristic records of Tuscany (central Italy) can be entered, stored, updated and freely accessed through the Internet. As of 5 January 2015, the database stores 67,360 floristic records, referable to 3578 accepted specific and subspecific taxa. Most records are based on published data (80.6% of the total), then by published herbarium specimens (15.1%) and on unpublished field data (3.8%); unpublished herbarium records account only for 0.5% of the stored data. At present, the most represented species is the fern Pteridium aquilinum (L.) Kuhn subsp. aquilinum (Dennstaedtiaceae) with 234 records for 219 localities, but 625 species are still represented only by one record for a single locality. Data acquisition is far from complete, but in slightly more than one year a massive amount of data was accumulated, and can be maintained up-to-date with relatively little effort. This could power several researches such as, for example, (1) taxonomic researches especially on species and genera in Tuscany and Italy; (2) studies on the distribution of diversity across administrative or ecological boundaries; (3) evaluation of conservation status of endangered taxa; and (4) static and dynamic range modelling and evolution niche studies.  相似文献   
90.
Recent evidences highlighted the presence of Lactococcus lactis during late cheese ripening. For this reason, the role of this microorganism, well known as dairy starter, should be reconsidered throughout cheese manufacturing and ripening. Thus, the main objective of this study was to develop a RT-qPCR protocol for the detection, quantification and determination of the viability of L. lactis in ripened cheese samples by direct analysis of microbial nucleic acids. Standard curves were constructed for the specific quantification of L. lactis in cheese matrices and good results in terms of selectivity, correlation coefficient and efficiency were obtained. Thirty-three ripened cheeses were analyzed and, on the basis of RNA analysis, twelve samples showed 106 to 108 CFU of L. lactis per gram of product, thirteen from 103 to 105 CFU/g, and in eight cheeses, L. lactis was not detected. Traditional plating on M17 medium led to loads ranging from 105 to 109 CFU/g, including the cheese samples where no L. lactis was found by RT-qPCR. From these cheeses, none of the colonies isolated on M17 medium was identified as L. lactis species. These data could be interpreted as a lack of selectivity of M17 medium where colony growth is not always related to lactococcal species. At the same time, the absence or low abundance of L. lactis isolates on M17 medium from cheese where L. lactis was detected by RT-qPCR support the hypothesis that L. lactis starter populations are mainly present in viable but not culturable state during ripening and, for this reason, culture-dependent methods have to be supplemented with direct analysis of cheese.  相似文献   
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